Plug-in type connector for a high current and high voltage circuit



1970 A. M. LOCKIE ETAL 3,551,881

PLUG-IN TYPE CONNECTOR FOR A HIGH CURRENT AND HIGH VOLTAGE CIRCUIT 2Sheets-Sheet 1 Filed Marqh 28, 1968 FIG.

INVENTORS Arthur M. Lockie 8 Merrill G. Leonard Dec. 29, 1970 A. M.LOCKIE TAL 3,551,881 -IN TYPE CONNECTOR FOR A HIGH CURRENT PLUG AND HIGHVOLTAGE CIRCUIT 2 Sheets-Sheet 2 Filed March 28, 1968 FIG.4.

United States Patent O 3,551,881 PLUG-IN TYPE CONNECTOR FOR A HIGHCURRENT AND HIGH VOLTAGE CIRCUIT Arthur M. Lockie, Sharpsville, Pa., andMerrill G.

Leonard, Fowler, Ohio, assignors to Westinghouse Electric Corporation,Pittsburgh, Pa., a corporation of Pennsylvania Filed Mar. 28, 1968, Ser.No. 716,841 Int. Cl. H01r 13/52 US. Cl. 339112 1 Claim ABSTRACT OF THEDISCLOSURE A plug-in type connector for high current-high voltagedistribution circuits comprising a stationary contact member and aplug-in contact member, and means for cooling gas generated when an arcoccurs between the stationary contact member and plug-in contact memberduring closing of the circuit.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to connectors wherein a plug-in member is plugged into astationary member to make an electrical circuit and, more particularlyto a plug-in type connector for connecting a distribution transformer toa high current-high voltage power transmission line.

Description of the prior art In the prior art plug-in type connectorsfor connecting a distribution transformer to a high current-high voltagetransmission line, the connector usually comprises a protrudingstationary contact connected to the transmission line with a protrudingrubber insulating member surrounding the stationary contact. Thestationary contact is usually hollow to provide for plugging the movableor plugin member into the stationary contact. The plug-in member isusually surrounded by an insulating sleeve of rubber or some other goodinsulating material. In order to plug the plug-in member into thestationary member it is necessary to stretch the rubber or insulatinghousing of the plugin member over the protruding rubber or insulatingmember of the stationary contact. With this type of construction, if anarc occurs between the contacts, when the stationary contact iscontacted by the movable contact, the hot gases generated by the arcwill build up sufficient pressure to distort and sometimes rupture therubber sleeve or housing surrounding the movable or plug-in contact. Insome cases the high temperature are builds up enough pressure toactually blow the movable or plug-in member away from the stationarycontact. This explosive force is sometimes sufficient to burst thesleeve or housing, or in other ways to destroy it or make it useless.The high temperature gas stream of this are is a good conductor ofcurrent; and, if the connector is close to a ground point, the arc mayform a circuit from the connector to ground which is very dangerous andundesirable. This objection to the prior art connectors is eliminated bythis invention by providing a vent having one end adjacent the point ofcontact of the stationary contact member with the movable or plug-incontact member, and with the other end of the vent connected to coolingmeans wherein the hot gases of the arc stream are cooled before they arereleased into the atmosphere. The cooled gases will then not conductcurrent and will not provide a circuit to the nearest ground, as is thecase with the high temperature are gases.

SUMMARY OF THE INVENTION This invention provides an improved plug-intype connector for connecting electrical apparatus such as adistribution transformer to a high voltage distribution cable.

3,551,881 Patented Dec. 29, 1970 also protected with a rubber or otherinsulating sleeve. To

plug the plug-in member into the stationary contact member the rubber orinsulating sleeve of the movable contact member must be stretched overthe protruding protected rubber or insulating member for the stationarycontact member. This results in relatively high friction drag, so it isditlicult to push the contacts together with a quick positive movement,and often upon momentary contact of the movable contact member with thestationary contact member an arc will start. This are generates hightemperature gases which expand with explosive forces. To prevent thesehigh temperature gases from blowing the movable contact member away fromthe stationary contact member and possibly ruining the movable contactmember a vent is provided which has one end thereof adjacent or near thepoint of contact between the stationary contact member and the movablecontact member and with the other end of the vent connected to a coolingarrangement for cooling the hot gases generated by the high temperaturearc. This cooling arrangement may take many different forms as long asit sufliciently cools the hot gases of the arc to a temperature at whichthey do not provide a good conductor of electricity. This cooling meansmay take the form of a chamber which is connected to the end of the ventopposite the end adjacent the contacts, which chamber will collect thehot gases generated by an arc and restrain the gases and graduallyrelease the gases to atmosphere after they have cooled to a pointwherein they no longer provide a good conductor for current. Thiscooling means may also take the form of a muffler connected to the endof the vent opposite the end adjacent the contact members, which mufilerrestricts the flow of the hot gases for a period of time long enough topermit the hot gases to cool to a temperature wherein they may bereleased to atmosphere without danger of them providing a current pathto ground. In both cases, the outside of the chamber and the outside ofthe mufiler cooling means are exposed to ambient temperature whichassists in reducing the temperature of the hot gases to a safetemperature before releasing them to the atmosphere. The chamber ormufller may be made of some good electrical insulating material, such aspolyester glass, or other suitable material.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation, with partsbroken away for clarity, illustrating one embodiment of this invention;

FIG. 2 is a sectional view taken along line 11-11 of FIG. 1;

FIG. 3 is a plan view, partially in section, illustrating a secondembodiment of this invention;

FIG. 4 is a plan view, partially in section, illustrating a thirdembodiment of this invention; and

FIG. 5 is a plan view, partially in section, illustrating a stillfurther embodiment of this invention.

DESCRIPTION OF PREFERRED EMBODIMENTS Throughout the description of thedrawings which follows, like reference characters illustrate like partsin each of the different figures.

Referring to FIG. 1 of the drawings, this figure illustrates a T-typeplug-in connector 10 for connecting a high voltage-high currenttransmission line 12 to the distribution transformer 15.

The T-connector comprises a stationary contact as sembly 14 which iselectrically connected to the transmission line 12. The contact assembly14 comprises four spring-like members 16 which are collectivelyconnected to the transmission line 12 and are arranged in substantiallya circle, as best illustrated in FIG. 2. The stationary contact assembly14 is surrounded by rubber or other insulating member 18 which protrudesfrom the insulation 22 of the transmission line 12 and completelysurrounds the stationary contact assembly 14. A vent 20 is providedthrough the insulation 22 around the high voltage cable 12. One end 24of the vent 20 terminates in the space or enclosure 13 provided by thecircular arrangement of the stationary contact fingers 16 and the otherend 26 of the vent terminates exteriorly of the insulation 20 around thecable 12. A chamber 28 is connected to the end 26 of the vent whichextends exteriorly of the insulation 22 around the cable 12. Thischamber 28 has a fairly large volume and the exterior of the chamber isexposed to the ambient temperature. Small bleed holes 30 are providedthrough the walls of the chamber 28.

The high voltage-high current transmission line 12 may be connected tothe distribution transformer 15 by means of a plug-in member 40. Theplug-in member comprises an electrical conducting element 42 which issurrounded by a rubber insulating sleeve or housing 44. The conductor 42is connected to a high voltage cable 44 which in turn is connected to ahigh voltage bushing 46 of the transformer 15. The other terminal of thetransformer 15 is connected to ground at 48. The insulating sleeve orhousing of the plug-in member 42 is slightly smaller than the protrudinginsulating member 18 of the stationary member 14, so that when theplug-' in member 42 is plugged into the stationary contact member 14 toconnect the transformer 15 to the transmission line 12 the insulatingsleeve or housing 44 for the plug-in contact 42 must be stretched overthe protruding insulating member 18 for the stationary contact assembly.14, and thereby provides a good electrical contact. At the same time,the housing 44 makes a tight fit over the protruding member 18, whichthus makes a moisture proof, air tight housing or enclosure aboutcontacts 14 and 42.

if not vented or disposed of will blow the movable contact structureaway from the stationary contact structure and oftentimes injures ordestroys the protecting sleeve or housing 44 of the movable contactmember. However, with the structure disclosed this cannot occur becauseany hot gases generated by an are are vented away from the contacts 14and 42 through the vent 20. These gases are trapped in the chamber 28and cooled to a temperature wherein they no longer provide a goodconductor. If these hot gases are released to atmosphere directly theywill provide a current path for the arc to the nearest ground. However,after these gases have been cooled to a temperature where it is safe torelease them to the atmosphere, they are gradually vented to theatmosphere through the very small vent holes 30 provided in thereservoir 28. This structure not only prevents the high temperature highpressure gases generated by the are from damaging or destroying theconnector but it also provides for means for safely discharging thesegases to the atmosphere without providing an arc circuit from thecontacts to the nearest ground. If the gases are vented directly to theatmosphere and an arc is allowed to form from the contacts to ground, inall probability the connector would be melted and destroyed before thearc is extinguished by the operation of back-up protective devices onthe line.

FIG. 3 of the drawings illustrates a second embodiment of thisinvention. The structure of FIG. 3, except for the means for cooling thehigh temperature-high pressure are gases comprising a baflie or muffler50 instead of a chamber, is similar to that disclosed in FIG. 1. As seenfrom FIG. 3 any high temperature-high pressure gases generated by an arebetween the contacts 14 and 42 are vented into a muffler 50. The mutfier50 contains a plurality of baffies 52 extending downwardly and aplurality of baffles 54 extending upwardly which provides a tortuouspath for the gases. This tortuous path will provide cooling for thegases before they are discharged to the atmosphere at 56. The outside ofthe muffler 50 is exposed to ambient temperature which assists in cooling the hot gases before they are released to the atmosphere.

FIG. 4 illustrates a still further embodiment of the invention. Thisembodiment utilizes a bafile or mufiler 50 of the type disclosed in FIG.3 and also provides a chamber or reservoir around the muffler 50 forfurther cooling and restricting the flow of the gases after they havepassed through the muffier 50. The reservoir 60 is also provided withvery small bleed holes or orifices 62 for bleeding the cooled gases fromthe reservoir 60 when the pressure builds up sufficiently in thereservoir 60.

FIG. 5 illustrates an embodiment of the invention wherein a chamber orreservoir is provided inside the sleeve 40 which surrounds the plug-incontact 42. The contact 42 is centered in this chamber 70 by means of aspider member 72.

In the embodiment of FIG. 5, if an arc ocurs between the contacts 42 and18, the hot arc gases will rise into the chamber 70 inside the sleeve40. After the gases have cooled in the chamber 70, they are bled back tothe enclosure 13 between the contact structure .14 and the end of thecontact member 42 through the spaces 17 between the spring fingers 16,see FIG. 2. The cooled gases are then slowly bled from the encolsure 13through the vent 20 to atmosphere. The vent 20 has substantially thesame configuration in this embodiment as in the embodiment of FIGS. 1,2, 3 and 4; except, that it has a very small cross-section. The purposeof the small cross-section of the vent 20 in this embodiment is to forcethe hot are gases to rise into the chamber 70 and thereby be cooledbefore they are released through the vent 20 to the atmosphere.

From the foregoing description taken in connection with the drawings, itis seen that this invention has provided a plug-in type connector forconnecting a high voltage-high current transmission line to adistribution transformer or the like; wherein, the distributiontransformer or the like may be plugged into the high voltagetransmission line with a fault on the transmission line and if an arcshould occur between the stationary contact member and the movablecontact member of the connector the high temperature-high pressure gasesgenerated by the arc may be vented from the connector and discharged tothe atmosphere without danger of having the high temperature-highpressure gases of the arc damage the connector or provide a current pathfrom the connector to the nearest ground. It is very important that thearc is not permitted to provide a current path from the connector to theground because when an arc occurs from the connector to ground thecircuit including the arc may become a very high kva. circuit which islimited only by the impedance of the transmission line and the currentdrawn often becomes so high that the connector will be completely meltedand destroyed. This invention provides an effective and economical meansfor preventing any such destructive are from developing from theconnector to ground, if an arc should occur when the plug-in connectorelement is plugged into the stationary contact of the connector.

We claim as our invention:

1. A connector for connecting a high voltage conductor to a branchconductor, said connector comprising a first body member having a hollowelectrical contact assembly mounted therein, a second body member havinga contact member mounted therein, the contact member of said second bodymember being insertable into the hollow contact structure of said firstbody member, a first enclosure formed by said hollow contact structureand one end of the contact member of said second body member when saidcontact member of said second body member is inserted into said hollowcontact structure, a second enclosure in said second body member, saidsecond enclosure surrounding said contact structure of said second bodymember, said second enclosure providing a gas cooling chamber for gasesgenerated when an arc occurs between said hollow contact structure andthe contact structure of said second body member, passage meansconnecting said second enclosure to said first enclosure, said firstbody member having a passage therein, said passage in said first bodymember having one end communicating with said first enclosure andanother end open to atmosphere exteriorly of said first body member,said passage in said first body member serving to vent cooled gases fromsaid second enclosure to atmosphere.

References Cited UNITED STATES PATENTS 2,223,975 12/1940 Traver 200-4491,535,148 4/1925 De Hart 339-111 2,802,998 8/1957 Bauer 339--1113,374,331 3/1968 Brockhaus et al. 339-111X 3,413,592 11/1968 Link339-l11 RICHARD E. MOORE, Primary Examiner US. Cl. X.R.

